Mechanical vibrator signalling device



7, 1962 J. E. VISTAIN, JR 3,048,144

MECHANICAL VIBRATOR SIGNALLING DEVICE Filed Jan. 9, 1961 I A4 lgvwzyrox.I Bifzmed' 6T MJ/Qln J/a 46 iv 2 f zmrmw ATTK 3,048,144 Patented Aug. 7,1962 free 3,048,144 MECHANICAL VIBRATOR IGNALLHNG DEVICE James E.Vistain, In, Slrokie, Ill, assignor to Admiral Corporation, Chicago,113., a corporation of Delaware Filed Jan. 9, 1961, Ser. No. 81,382Claims. (Cl. 116-437) This invention relates to a signal generatingdevice of the sonic or supersonic resonator variety, and morespecifically to a novel means of exciting the resonator of such a deviceand automatically resetting the exciting mechanisms.

Signal generating units of the type generally employing alongitudinal-mode resonator rod and a striking hammer are now well knownin the art of remote control electronic devices. Vibrations ofaccurately predetermined frequency and prolonged intensity can beproduced mechanically by applying a single, discrete blow to one end ofsuch a resonator if it is nodally supported for minimum damping. Inorder to be commercially feasible the mechanical'means for deliveringthe required discrete blow and resetting itself must be easily operated,effective, and economical to manufacture. For most effective operationthe hammer applying the actuating blow must strike with considerableenergy but be definitely restrained from striking a second time anddamping the resultant vibration.

Accordingly, it is an object of this invention to provide a manuallyoperable striking mechanism for a longitudinal-mode resonator rod thatwill impart maximal vibrational energy to the rod with minimal damping.

Another object of this invention is to provide an economical but easilyoperable ultrasonic transmitter capable of producing a signal ofpredetermined frequency and prolonged high amplitude.

A further object of this invention is to provide a simpleresonator-actuating mechanism that can deliver a single, discrete blowto the resonator and return itself to its original pre-actuationposition.

An additional object of this invention is to provide a novel combinationof a toggle mechanism, a spring restrained striking hammer actuatedthrough the toggle mechanism and associated linkage to deliver a single,discrete blow to the end of a longitudinal-mode resonator rod, and anoverriding return spring.

Moreover, it is an object of this invention to provide a novel remotecontrol transmitter with a high energy signal produced by entirelymechanical means.

Other objects of this invention are to provide the above features andadvantages together with a damping element that is selectivelyengageable with the resonator rod to halt signal transmission whendesired.

Still other and further advantages and objects of the present inventionwill become apparent from examination of the detailed disclosure anddrawings in this case and from a reading of the claims. l

A preferred embodiment of this invention is illustrated by theaccompaning drawings in which:

FIGURE 1 is a side elevation of the signalling device, showing it in itsunactuated or rest position.

FIGURE 2 is a side elevation, with the resonator rod mounting shown insection, of the signalling device, of FIGURE 1 in its actuated positionat the instant of impact between the hammer and the resonator rod.

FIGURE 3 is an enlarged cross-sectional view taken along line 33 ofFIGURE 2 and showing in detail the mounting for the resonator bar.

Referring now to the drawings, in which like elements are designated bylike reference numbers, a solid cylindrical, longitudinal-mode resonatorrod is provided with an annular groove 12 midway between its ends, bymeans of which the rod 10 is received and supported between two portionsof a flexible diaphragm. Diaphragm portion 14 is disposed in the lowerhalf and diaphragm portion 15 in the upper half of a circular hole 16 ina projecting flange portion 18 of a flat mounting plate 20, so that theresonator rod is loosely held between the portions 14 and 15 and causedto lie parallel to and adjacently spaced apart from the mounting plate20.

Also mounted on plate 20 are first and second lever assemblies 22 and 24respectively and four stops (26, 28, 3d and 32). The first leverassembly 22 is spaced farther from the plate 20 than is the second leverassembly 24 so as to provide rotational clearance between theiroverlapping arms.

First lever assembly 22 comprises a short arm 34 extending verticallypast the right end of the horizontally disposed rod Iii and a long arm35 extending horizontally above rod 10 and being integrally attached toshort arm 34 at its upper end. The assembly 22. is pivota ly mounted onvertical plate 20 through a pin 36'. A notch 38 is provided in the lowerright portion of short arm 34 for receiving the end hook portion 40 of ahorizontally disposed helical tension spring 42. The left end of spring42 is provided with a hook portion 44 which is received in a hole 46 inflange 18 so that spring 42 acts in tension between flange l8 and shortarm 34 to provide a strong clockwise moment to assembly 22. A pushbutton 54 is mounted on the top portion of long arm 35 approximatelymid-way between its ends. Notches 56 and 58 are provided in long arm 35near its pivot end for receiving a heavy damping wire 60. The dampingwire 60 is securely wrapped around arm 35 and extends downwardly fromarm 35, terminating in a curved portion 62 that lies opposite rod It andis engageable with its right end to effect dampening of its vibrations.Stops 26 and 28 are vertically spaced apart on plate 20 and areengageable with the upper and lower edges respectively of long arm 35thereby limiting its rotational movement to about ten degrees. Arm 35 isprovided at its free end with a small hole 50 adapted to receive one leg51 of a bi-stable torsion spring 52.

Second lever assembly 24 is pivotally mounted on plate 20 through ashaft 64 that is positioned slightly to the left of the free end of arm35 and opposite the approximate center of the ten degree are segmentdescribed by its free end. The assembly 24 comprises a short leg 66extending generally to the right from shaft 64 and an integral, longer,arcuate leg 70 extending generally to the left from shaft 64, thendownwardly, and finally to the right, terminating in an upturned flangeportion 72. The flange portion 72 is provided with a hole 74 for looselyreceiving the shaft 76 of a hammer 78. Stops 3i) and 32 are angularlyspaced apart on plate 20 and are engageable with the top (or back) edgeand the bottom (or front) edge, respectively, of arcuate arm 70, therebylimiting its rotational movement to about 45 degrees. Flange 72 ispositioned to be vertically perpendicular to plate 20 and opposite theleft end of rod 10 when arm 70 is against its lower stop 32. The hammer78 is provided with a curved striking face 80 aligned for percussiveengagement with the left end of rod lil. The left end of hammer 78 isprovided with a pyramidal knob 82, the base of which provides a shoulderfor restraining a compression spring 84 that is helically wound aboutshaft 76. The right end of spring 84 bears against the back of flange 72and normally urges the hammer 78 into engagement with the front surfaceof flange 72 and out of engagement with the adjacent left face of theresonator rod 10. Short leg 66 is provided at its free end with a smallhole 68 adapted to receive a second leg 69 of torsion spring 52.

The bi-stable torsion spring 52 comprises a single segment of springwire helically wound about 420 degrees so that its two end portions 51and 69 are of equal length,

protruding from the coil portion at an angle of about 120 degrees fromone another in the unstressed position. The end of each portion 51 and69 is crooked away from the plane of the coil portion and is adapted forreception in holes 50 and 68 respectively of the first and second leverassemblies. The spring 52 is inserted in the assembly of FIGURE 1 orFIGURE 2 by elastically pinching together the leg portions 51 and 69 sothey diverge by about 30 degrees and inserting the crooked portions inthe holes provided. Spring 52 will then be disposed between the planesof lever assembly 22 and lever assembly 24 so as not to interfere withthe rotational movement of either, and it will constantly urge the arm35 apart from the leg 66 in the manner of a compression spring. As willbe seen from the ensuing description of the actuation and recoverymovements, the spring 52 may apply either the combination of a clockwisemoment to lever assembly 24 and a counter-clockwise moment to leverassembly 22 (FIGURE 1) or the opposite combination (FIGURE 2) dependingon the relative positions of the arm 35 and the leg 66.

Excitation of the resonator rod through the mechanisms just describedrequires only that the knob 54 be pressed downward. When the knob isreleased, the mechanisms will return to their rest positions of FIGURE 1and the vibrations will be damped. These reciprocal movements ofactuation and recovery are described in detail in the followingparagraphs.

During the actuation movement, as the button 54 is depressed, the firstlever assembly 22 is caused to rotate counter-clockwise about itspivotal pin 36 and away from its rest-position stop 26. The bi-stabletorsion spring 52, which is biased to urge its leg portions 51 and 69away from one another and thereby acts as a special type of compressionspring between its points of connection to lever assemblies 22 and 24,first urges the second lever assembly 24 against its rest-position stop30 because its effective moment on lever assembly 24 is clockwise.However, as the point of connection between the first lever assembly 22and its leg 51 of the torsion spring 52 passes the radial line betweenthe axis of rotation of the second lever assembly 24 and the point ofconnection of the second lever assembly 24 with its leg 69 of thetorsion spring 52, the torsion spring 52 begins to effect acounter-clockwise moment on the second lever assembly 24 away from itsrest-position stop 30. Since this counterclockwise moment is resistedonly by the inertia of the second lever assembly 24 and by smallfrictional forces, the second lever assembly 24 and the hammer assembly78 mounted thereon are rapidly accelerated counterclockwise until thelever assembly 24 strikes the actuation-position stop 32. At this momentthe lever assembly 24 suddenly stops, but the momentum of the hammer 78continues to carry it forward against the compressive force of itsassociated spring 84. The springs 52 and 84, the spacing between theresonator rod 10 and the hammer face 80, and the masses of the hammerand lever parts =are'carefully designed so that the hammer 78 will haveenough momentum to enable it to strike the rod 10 in a single sharpblow, but that after rebounding from the rod 10 the hammer will berestrained by spring 84 from rebounding ofi of flange 72 and againstriking the reso nator rod 10. This single sharp blow is necessary toproduce the greatest amplitude of emitted vibration from the resonatorrod.

It should also be noted that the actuation movement rotates the dampingwire 60 away from contact with the resonator rod 10 before the hammer 78strikes, and that the return spring 42 is additionally energized by thesame counter-clockwise rotation of the first lever assembly 22.

The return spring 42 is so designed and located as to apply a greaterrotational moment to the first lever 22 than does the torsion spring 52when in the actuation position, so when the pressure on button 54 isreleased the clockwise moment of spring 42 will overpower thecounter-clockwise moment of spring 52 and return the mechanisms to theirrest-positions. During the recovery movement, the torsion spring 52 willapply a counter-clock- Wise moment to the second lever assembly 24,urging it against its actuation position stop 32 until the point ofconnection between the first lever assembly 22 and its leg 51 of thetorsion spring 52 reaches the radial line between the axis of rotationof the second lever assembly 24 and the point of connection of thesecond lever assembly 24 with the leg 69 of the torsion spring 52. Thenthe torsion spring 52 begins to apply a clockwise moment to the secondlever assembly 24 which is resisted only by small inertial andfrictional forces and causes the second lever assembly 24 to snap backagainst its restposition stop 3%. The recovery movement brings dampingwire 6% back against the end of rod 10, rapidly damp ing the vibrationsof rod 16.

The materials of construction of the mounting plate, the stops, thelever assemblies, shafts and flange portions are not critical, but maybe of cast iron, rolled steel or lighter weight metal, or even plastics.The resonator rod should be of brass, aluminum, or other speciallychosen material with low internal damping. It should be cut precisely tothe length required for the frequency desired to be emitted and shouldbe nodally mounted, as at its exact longitudinal center, through aflexible, non-restraining mount having minimal area of contact with therod. The hammer should be of hard steel or alloy material and have amass chosen to provide optimum striking characteristics. The diaphragmmay be of rubber or valious other Suitable material, and may be held inposition on its flange by an adhesive or by an auxiliary clamping plate.The stops may be cushioned and should preferably be positioned oppositethe center of percussion of the levers with which they act. The knob maybe of any suitable plastic material, and the damping wire may be ofsteel or other metal.

Numerous other modifications not specifically mentioned herein may beemployed without departing from the spirit and scope of this invention,and it is not intended to limit the scope of the appended claims by theomission from this disclosure of such modifications.

What is claimed is:

1. In combination with a mechanical vibrational wave generator elementfor generating a vibrational wave of predetermined frequency and highinitial amplitude responsive to impact by a hammer, exciter meansincluding: a hammer carrier mounted for rotational movement; a hammermounted to said hammer carrier for percussive engagement with saidgenerator element; means, including a coil spring resiliently mountingsaid hammer on said hammer carrier, said spring normally maintainingsaid hammer in a first position relative to said hammer carrier; anoperating lever having an actuated and a rest position; an over-centerspring coupled between said operating lever and said hammer carrier;means normally biasing said operating lever to said rest position; saidover-center spring being effective to rotationally accelerate saidhammer carrier toward said generator element upon said opcrating leverbeing moved from said rest to said actuated position; and stop meansabruptly stopping the movement of said hammer carrier near saidgenerator element, said hammer rapidly moving into percussive engagementwith said generator element and rebounding therefrom; said coil springbeing effective to retract said hammer to said first position, whereby asingle percussive contact between said hammer and said generator elementis obtained.

2. A mechanical generator for generating an ultrasonic wave ofpredetermined frequency comprising: support means, a longitudinal modevibrator element resonant at said predetermined frequency and nodallymounted on said support means; a hammer for percussive engagement withone end of said vibrator element; hammer carrying means rotationallymounted on said support means; means resiliently mounting said hammer onsaid hammer carrying means; an actuation lever movably mounted on saidsupport means; means normally urging said actuation lever to its restposition; toggle action spring means coupling said actuation lever andsaid hammer carrying means; first and second stop elements mounted onsaid support means, said hammer carrying means being normally urgedagainst said first stop element by said actuation lever and said toggleaction spring means; said toggle action spring means rotationallyaccelerating said hammer carrying means away from said first stopelement and into engagement with said second stop element responsive tosaid actuation lever being moved to its actuated position, whereby saidhammer carrying means is stopped abruptly; said hammer rapidly movinginto percussive engagement with said end of said'vibrator element andrebounding therefrom; the means resiliently mounting said hammer actingto retract said hammer upon rebound after initial impact to preventfurther contact between said hammer and said vibrator element.

'3. A mechanical generator for generating a compressional wave ofpredetermined frequency comprising: support means, a vibrator elementresonant at said predetermined frequency mounted on said support means;a hammer for percussive engagement with said vibrator element; hammercarrying means rotationally mounted on said support means; meansresiliently mounting said hamrner on said hammer carrying means; anactuation lever movably mounted on said support means; means normallyurging said actuation lever to its rest position; toggle action springmeans coupling said actuation lever and said hammer carrying means;first and second stop elements mounted on said support means, saidhammer oarrying means being normally urged against said first stopelement by said actuation lever and said toggle action spring means;said toggle action spring means rotationally accelerating said hammercarrying means away from said first stop element and into engagementwith said second stop element responsive to said actuation lever beingmoved to its actuated position, whereby said hammer carrying means isstopped abruptly; said hammer rapidly moving into percussive engagementwith said vibrator element and rebounding therefrom; the meansresiliently mounting said hammer acting to retract said hammer uponrebound after initial impact to prevent further contact between saidhammer and said vibrator element; and damping means coupled to andmovable with said actuation lever contacting said vibrator element whensaid actuation lever is in said rest position.

4. A mechanical generator for generating an ultrasonic wave ofpredetermined frequency comprising: support means, a longitudinal modevibrator element resonant at said predetermined frequency and nodallymounted on said support means; a hammer for percussive engagement withone end of said vibrator element; a vibration damper engaging saidvibrator element at its other end; hammer carrying means rotationallymounted on said support means; a coil spring resiliently mounting saidhammer on said hammer carrying means; an actuation lever movably mountedon said support means; means normally urging said actuation lever to itsrest position; an over center spring coupling said actuation lever andsaid hammer carrying means; first and second stop elements mounted onsaid support means, said hammer carrying means being normally urgedagainst said first stop element by said actuation lever and said overcenter spring; said over center spring rotationally accelerating saidhammer carrying means away from said first stop element and intoengagement with said second stop element responsive to said actuationlever being moved to its actuated position, whereby said hammer carryingmeans is stopped abruptly; said hammer rapidly moving into percussiveengagement with said end of said vibrator element and reboundingtherefrom; the coil spring resiliently mounting said hammer acting toretract said hammer upon rebound after initial impact to prevent furthercontact between said hammer and said vibrator element; and means coupledto said actuation lever moving said vibration damper out of engagementwith said vibrator when ever said actuation lever is out of its restposition.

5. A mechanical generator for generating an ultrasonic wave ofpredetermined frequency comprising: support means, a longitudinal modevibrator element resonant at said predetermined frequency and nodallymounted on said support means; a hammer for percussive engagement withone end of said Vibrator element; a vibration damper engaging saidvibrator element at its other end; hammer carrying means rotationallymounted on said support means; a coil spring resiliently mounting saidhammer on said hammer carrying means; an actuation lever movably mountedon said support means; spring means normally urging said actuation leverto its rest position; an over center spring coupling said actuationlever and said hammer carrying means; first and second stop elements Mmounted on said support means, said hammer carrying means being normallyurged against said first stop element by said actuation lever and saidover center spring; said over center spring rotationally acceleratingsaid hammer carrying means away from said first stop element and intoengagement with said second stop element responsive to said actuationlever being moved to its actuated position, whereby said hammer carryingmeans is stopped abruptly; said hammer rapidly moving into percussiveengagement with said one end of said vibrator element and reboundingtherefrom; the coil spring resiliently mounting said hammer acting toretract said hammer upon rebound after initial impact to prevent furthercontact between said hammer and said vibrator element; means coupled tosaid actuation lever moving said vibration damper out of engagement withsaid vibrator element whenever said actuationlever is out of its restposition, said spring means being stronger than said over center springto insure return of said actuation lever to its rest position uponrelease thereof.

2,821,955 Ehlers Feb. 4, 1958 Rinker Oct. 21, 1958

